A Device-to-Device (D2D) technology refers to that neighboring terminal equipments may perform data transmission in a direct link manner in a short-distance range and a network equipment for forwarding is not required. A licensed frequency band resource may be shared between D2D communication and a cellular system to form a unified hybrid cellular-D2D network. In the hybrid network, part of terminal equipment may still work in a cellular communication mode, namely communicating with other terminal equipment through network equipment, while part of terminal equipment may work in a D2D communication mode, namely performing direct data transmission with the other terminal equipment through D2D links with the other terminal equipment.
In addition, data transmission between network equipment and terminal equipment may be assisted through a D2D relay, and at this moment, a D2D communication mode is adopted between the D2D relay and a D2D terminal, while a cellular communication mode is used between the D2D relay and the network equipment. The D2D relay receives and forwards data in a half duplex manner, and performs mode switching in a receiving and forwarding process.
In a conventional art, a D2D relay relays data transmission between a D2D terminal and network equipment through an Internet Protocol (IP) layer (i.e., Layer 3 (L3)), and for a received data packet, is required to perform de-capsulation processing sequentially through Layer 1 (L1) (i.e., a Physical (PHY) layer), Layer 2 (L2) (including a Media Access Control (MAC) layer, a Radio Link Control (RLC) layer and a Packet Data Convergence Protocol (PDCP) layer) and L3 and perform encapsulation processing sequentially through L3, L2 and L1 to implement data relaying. Therefore, complexity is relatively high, and a data processing delay is relatively long.